ZOOKEEPER-4940: Enabling zookeeper.ssl.ocsp with JRE TLS provider errors out

add docs
add new property for tcnative OCSP setting
rename property
factor out the stapling handling code to a new method
use and honor OpenSSL.isOcspSupported()
Add more log messages
Remove comments about BoringSSL not supporting OCSP stapling
rearrange code to make patch smaller
add comment for clarification
remove new property
Reviewers: anmolnar
Author: stoty
Closes #2270 from stoty/ZOOKEEPER-4940

zookeeper-server/src/main/java/org/apache/zookeeper/common/ClientX509Util.java

diff --git a/zookeeper-server/src/main/java/org/apache/zookeeper/common/ClientX509Util.java b/zookeeper-server/src/main/java/org/apache/zookeeper/common/ClientX509Util.java
index 9aa03ae..561b865 100644
--- a/zookeeper-server/src/main/java/org/apache/zookeeper/common/ClientX509Util.java
+++ b/zookeeper-server/src/main/java/org/apache/zookeeper/common/ClientX509Util.java
@@ -19,6 +19,7 @@
 package org.apache.zookeeper.common;
 
 import io.netty.handler.ssl.DelegatingSslContext;
+import io.netty.handler.ssl.OpenSsl;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslContextBuilder;
 import io.netty.handler.ssl.SslProvider;
@@ -79,7 +80,7 @@ public SslContext createNettySslContextForClient(ZKConfig config)
             sslContextBuilder.trustManager(tm);
         }
 
-        sslContextBuilder.enableOcsp(config.getBoolean(getSslOcspEnabledProperty()));
+        handleTcnativeOcspStapling(sslContextBuilder, config);
         String[] enabledProtocols = getEnabledProtocols(config);
         if (enabledProtocols != null) {
             sslContextBuilder.protocols(enabledProtocols);
@@ -123,7 +124,7 @@ public SslContext createNettySslContextForServer(ZKConfig config, KeyManager key
             sslContextBuilder.trustManager(trustManager);
         }
 
-        sslContextBuilder.enableOcsp(config.getBoolean(getSslOcspEnabledProperty()));
+        handleTcnativeOcspStapling(sslContextBuilder, config);
         String[] enabledProtocols = getEnabledProtocols(config);
         if (enabledProtocols != null) {
             sslContextBuilder.protocols(enabledProtocols);
@@ -144,6 +145,17 @@ public SslContext createNettySslContextForServer(ZKConfig config, KeyManager key
         }
     }
 
+    private SslContextBuilder handleTcnativeOcspStapling(SslContextBuilder builder, ZKConfig config) {
+        SslProvider sslProvider = getSslProvider(config);
+        boolean tcnative = sslProvider == SslProvider.OPENSSL || sslProvider == SslProvider.OPENSSL_REFCNT;
+        boolean ocspEnabled = config.getBoolean(getSslOcspEnabledProperty());
+
+        if (tcnative && ocspEnabled && OpenSsl.isOcspSupported()) {
+            builder.enableOcsp(ocspEnabled);
+        }
+        return builder;
+    }
+
     private SslContext addHostnameVerification(SslContext sslContext, String clientOrServer) {
         return new DelegatingSslContext(sslContext) {
             @Override

zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java

diff --git a/zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java b/zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java
index e4f19d7..71d14f4 100644
--- a/zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java
+++ b/zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java
@@ -740,6 +740,20 @@ public void testCreateSSLContext_validCustomSSLContextClass(
         assertEquals(SSLContext.getDefault(), sslContext);
     }
 
+    @ParameterizedTest
+    @MethodSource("data")
+    public void testCreateSSLContext_ocspWithJreProvider(
+            X509KeyType caKeyType, X509KeyType certKeyType, String keyPassword, Integer paramIndex)
+            throws Exception {
+        init(caKeyType, certKeyType, keyPassword, paramIndex);
+        ZKConfig zkConfig = new ZKConfig();
+        try (ClientX509Util clientX509Util = new ClientX509Util();) {
+            zkConfig.setProperty(clientX509Util.getSslOcspEnabledProperty(), "true");
+            // Must not throw IllegalArgumentException
+            clientX509Util.createSSLContext(zkConfig);
+        }
+    }
+
     private static void forceClose(Socket s) {
         if (s == null || s.isClosed()) {
             return;